12 × 12 deck cost & materials
Short answer
A 12 × 12 ft deck is 144 square feet. In composite it costs about $4,320–$8,640 installed and needs roughly 22 deck boards and 10 joists.
Area
144 sq ft
Composite cost
$4,320–$8,640
Deck boards
22
Joists
10
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Frequently asked questions
How many deck boards for a 12 × 12 deck?
About 22 16-ft boards (5½" wide) for 144 sq ft, including 10% waste. Longer boards mean fewer pieces but more offcuts.
How much does a 12 × 12 deck cost?
A composite 12 × 12 deck costs about $4,320–$8,640 installed. Pressure-treated wood is cheaper; PVC costs more.
How many joists for a 12 × 12 deck?
About 10 joists at 16" on center, plus 6 footings. Enter your exact size and spacing in the calculator.